Efficient light conversion with perovskite nanocrystals

Certain perovskites do have this desirable property.

Perovskite lattice. Credit: Wikimedia Commons.
Perovskite lattice. Credit: Wikimedia Commons.

A new study by the UvA-IoP physicists suggests that certain perovskites do have this desirable property. Certain crystals show very interesting properties at the nanoscale. There, we enter the world of nanocrystals, structures that are extremely useful in constructing technological applications at tiny scales.

At the point when semiconductors – in sunlight based cells, for instance – convert the vitality of light into electricity, this generally occurs one particle at any given moment. A solitary infalling photon results in a single energized electron (and the comparing ‘hole’ where the electron used to be) that can convey an electrical current.

Be that as it may, in specific materials, if the infalling light is sufficiently vigorous, advance electron-hole sets can be energized subsequently; this procedure is known as transporter duplication.

At the point when carrier multiplication occurs, the transformation from light into power can turn out to be significantly more proficient. For instance, in common solar cells, there is a hypothetical limit (the supposed Shockley-Queisser limit) on the measure of vitality that can be changed over—at most, a little more than 33 percent of the solar power gets transformed into electrical power. In semiconductor nanocrystals under the carrier multiplication impact, in any case, a most extreme effectiveness of up to 44 percent is anticipated.

Scientists sought this carrier multiplication effect in perovskites. Now, de Weerd, Gomez and Gregorkiewicz, along with their collaborators, report this phenomenon. Using spectroscopy methods, the researchers showed that perovskite nanocrystals made out of cesium, lead and iodine display carrier multiplication.

Moreover, they argue that the efficiency of this effect is higher than reported thus far for any other material; with this finding, the extraordinary properties of perovskites receive a new boost.

De Weerd, who successfully defended her Ph.D. thesis based on this and other research last week, says, “Until now, carrier multiplication had not been reported for perovskites. That we have now found it is of great fundamental impact on this upcoming material. For example, this shows that perovskite nanocrystals can be used to construct very efficient photodetectors, and in the future perhaps solar cells.”

The study is published in the journal Nature Communications.